A rescue helicopter has recovered one pilot while efforts continue to save others. Russian media quoting Russia's Ministry of Defense carried conflicting reports saying that the pilots ejected and that one of the jets may have managed to stay airborne.

However, all news from Russia indicates one of the fighter-bombers crashed into the Sea of Japan.

The Sukhoi Su-34 Fullback represents one of Russia's newer and more advanced fighter aircraft. It has two-seats, so the crash likely involved four people. The fighter-bomber has a maximum range of 2,485 miles, and a payload of up to 26,455 pounds, or 12 missiles under the wings.

The Su-34 jets have seen extensive use in Syria after being introduced into service in mid-2014.

Following the Friday morning collision, Russia has grounded flights of all Su-34s.

In September, the US grounded all F-35 flights after one of the jets crashed in South Carolina.